Method of producing concrete block



Oct. 30, 1962 F. c. MARTIN 3,060,542

METHOD OF PRODUCING CONCRETE BLOCK Filed Oct. 25, 1960 2 Sheets-Sheet 122 I I n filming I! n Hiilh.

INVENTOR.

FERDINAND c. MARTIN ATTOR N EY Oct. 30, 1962 c, MARTIN 3,060,542

METHOD OF PRODUCING CONCRETE BLOCK Filed 001:. 25, 1960 2 Sheets-Sheet 2INVENTOR. FERDINAND c. MARTlN ATTOR United States Patent 3,060,542METHOD OF PRGDUCENG CONCRETE BLOCK Ferdinand C. Martin, 3575 W.Clarendon, Phoenix, Ariz. Filed Get. 25, 1960, Ser. No. 64,920 4 Claims.(Ci. 2.5154) My invention relates to an improved method of producing aconcrete block. It relates more in particular to an improved method forproducing a concrete block of the type known in the art as a slump blockbut having the feature that at least one face of the block to whichplaster or the like is normally attached has a regular configuration andmay optionally comprise a different material than the main portion ofthe block.

Concrete blocks have been made for a large number of years. A commonmethod used to produce them in early stages was to tamp a relatively dryconcrete mix into a mold, the bottom of which comprised a pallet and thesides of which were gated so that they could be dropped away from thecompletely cast block to permit its removal on the pallet. While thismethod of producing concrete blocks permitted production of non-planarfinished faces, it had the disadvantage that the method involved the useof a relatively large amount of labor with attendant cost. In modernpractice concrete blocks are formed by use of fully automatic orsemi-automatic equipment, employing a relatively dry mix and areconventionally projected from the molds by direct vertical pressure sothat the side faces are planar and relatively rough. While blocksproduced in this manner are relatively inexpensive and may have verydesirable structural characteristics, they make an uninteresting sidewall from an architectural standpoint; and when used normally require anexterior finish.

To improve concrete blocks, particularly from an architecturalstandpoint, the so-called slump block has been developed in relativelyrecent years and has gone into somewhat general, if specialized, use.Such blocks can normally be produced by means of available fullyautomatic or semi-automatic forming equipment by first forming them in amold somewhat deeper than the mold employed for conventional concreteblocks, and a mold deeper than the final vertical dimension of theblock, and after being formed and ejected from the mold they arecompressed vertically between top and bottom surfaces, normally byhydraulic pressure. The block resulting from the final step of theprocess, commonly called the slumping step, has the same verticaldimensions as the conventional concrete block which it would replace,but the sides become slumped and take on an irregular random shape, sothat the faces of no two blocks are exactly identical. The slump blockof the prior art, however, has a disadvantage in that all verticalsurfaces have been the same characteristic of irregular random shape,and the rear surface of a wall made from such blocks is highlyirregular. This kind of irregular surface can be used for directapplication of plaster, although the plaster coat will be verynon-uniform in thickness and a good finish is extremely difficult andcostly to obtain. In modern building construction, however, it is acommon practice to furr out the plaster or wall board by means ofvertical strips. Tht plaster and wall are thereby separated, withresulting advantage from an insulation and other standpoints by thethickness of the strips used in the furring operation. Because of theuneven character of the slump blocks of the prior art, uniformapplication of furring strips is exceedingly difficult. The result isthat slump blocks, although presenting certain very definite advantagesfrom an architectural standpoint over the conventional flat sidedconcrete block, have not come into such general use as their finishedappearance would warrant.

Accordingly, a principal object of the present invention is theprovision of an improved method for producing a concrete block havingboth the advantages of a slump block and the advantages of the usualfiat faced concrete block of the prior art.

Still another object is the provision of a method for producing a slumpblock in which the random irregular shape characteristic of such blockis confined to surfaces which are not ordinarily finished by theapplication of plaster or the like.

A further object of the invention is the provision of an improved methodfor producing a concrete building block.

A still further object is the provision of an improved method forproducing a slump block or the like in which one vertical face of theblock is finished smooth and optionally of a different material than theremaining portion of the block.

Other specific objects and features of the invention will be apparentfrom the following detailed description taken with the accompanyingdrawings, wherein FIG. 1 is a perspective view showing the first stagein constructing an improved slump block in accordance with the presentinvention;

FIG. 2 is an end View of the partly finished block as illustrated inFIG. 1 and also indicates schematically the final step in itsproduction;

FIG. 3 is a view similar to FIG. 2 but showing the final step in theproduction of the block;

FIG. 4 is a perspective view similar to FIG. 1 but showing the completedblock;

FIG. 5 is a view similar to FIG. 1 but showing a modified form of blockjust prior to its final processing stage;

FIG. 6 shows still another manner of producing the block;

FIG. 7 shows the completed block resulting from further treatment of theFIG. 6 blank, and

FIG. 8 is a fragmentary front perspective view showing the structure ofa typical finished block.

In the general practice of my invention I first mold a blank forslumping, as in the prior art method, except that at least onelongitudinal wall is molded to the same vertical height which will becharacteristic of the final block after slumping. The front wall, andoptionally at least a portion of the end walls of the block, are firstmolded with a vertical dimension greater than the final dimension, sothat when the slumping step is performed only the front face andoptionally the end faces of the block will take on an irregular randomexterior configuration, leaving the rear face of the block planar and invertical relation with both the top and bottom faces.

In producing the slump block of the present invention, conventionalmolding equipment may be employed, modifying the same, particularly themold, only sufficiently to produce the modified blank which is subjectedto the slumping or vertical pressure step. All such equipment isprovided with means for vibrating the mold so that the mold becomesentirely filled with the concrete mix employed and all excess concreteis removed from above the mold so that the mold cavity is exactlyfilled. In the semi-automatic equipment the bottom face of the mold isnormally movable, and the entire mold is turned over and the bottom ofthe mold moved vertically to extrude the finished cast block. When theblock is slumped, the mold is designed so that the movable bottom areacontinues its vertical movement after ejection and performs the slumpingoperation by pressing the removed concrete casting down to the requiredvertical dimension. In the fully automatic type machine, the wetconcrete casting is normally ejected without turning the mold over, andwhen u a slump block is made a separate pressure plate descends to applyvertical slumping pressure to the wet block. It does not appearnecessary to an understanding of the present invention to illustrate theparticular arrangement of equipment commonly employed to form concreteblocks. I have, however, indicated in the drawings, as will be pointedout, the separate pressure plate commonly used on the fully automatictype equipment. It should be understood of course however, that theinvention is not limited to the particular type of machinery employed.In FIGS. 1 through 4 of the drawings I illustrate the method ofproducing the improved slump block of the present invention and show afinished block resulting from the method. The blank shown in FIG. 1 isproduced by means of any suitable mold using any of the availableequipment. The blank has a front wall 10, end walls 11 and 12, rear wall13 and the usual center web 14, leaving usual air spaces 16 and 17common to one type of building block. It will be noted that the frontwall 10 has a substantially greater vertical dimension than the sidewalls 11 and 12 and the rear wall 13. These latter are molded to thesame vertical dimension which the final block will have. The differencein vertical dimension between the front wall 10 and the remainingportions of the blank shown in FIG. 1 is determined by the amount ofslumping desired. A good rule of thumb to produce a nice appearing blockis to make the vertical dimension of the front wall 10 one inch greaterthan the remaining portion of the blank. A common block of the typeshown, for example, has an overall length of about 15 /2 inches, a widthof about 7 /4 inches and a height of about 3% inches. When producingsuch a block the vertical dimension of the front wall 10 may optionallybe, for example, about 4 /s inches. It will be noted also that a recess18 is also formed between the front wall and the contiguous end wallsand web 14. This is to provide for the ready and uniform flow of theconcrete during the slumping operation.

The blank shown in FIG. 1, as already stated, can be produced on anyusual type of equipment employing a suitable mold with of course thecommonly used vibration to assure filling out of the mold and propersetting up of the aggregate. Since, however, the aggregate is at leastpartly deformed during the slumping operation it is desirable that thecement used contain an adequate amount of plasticiser to permit freeflow. A suitable cement is readily obtainable from many sources and iscommonly sold as plastic cement. The aggregate used in producing theblock of my invention may be substantially identical with the aggregateused in conventional concrete I blocks but the amount of cement in thematrix and the amount of water are also somewhat increased so that asofter, potentially somewhat higher strength material is used. As anexample, if a specification should call for a final compressive strengthof 1,500 pounds per square inch I would employ a mix which theoreticallywould yield a final compressive strength of about 2,000 pounds persquare inch. If the mold producing the blank shown in FIG. 1 isorientated in the same position as the blank shown in FIG. 1, it is ofcourse necessary that the wiping action at the top of the mold removethe excessive material differentially, leaving the front wall 10 at theelevation shown, and the remaining portion of the block at a uniformlower elevation. The blank, however, may be formed in a mold reversedwith respect to FIG. 1, in which case the blank shown in FIG. 1 can beinverted as it is removed from the mold. In any event, the blank shownin FIG. 1 is supported on a suitable base 21 as shown in FIG. 2 as it isremoved from the mold, and a top plate 22 brought down under suitablepressure to the position shown in FIG. 3. It should be noted that as thepressure plate 22 moves downwardly it stops at the very top edge of thatportion of the blank defined as the end walls and the back wall, but inits movement it compresses and slumps the front wall 10 to produce afront wall 10' having a slumped front face of random irregular shape,but having the same vertical height as the remaining portion of theblock. The recess 18 is filled by the flowing of the wet concrete sothat the end walls 11 and 12 are imperforate and of conventional shape,depending upon the amount of slumping action there may be from bulgingof part of the face of the end walls 11 or 12 or the web wall 14, but inno event is the rear Wall 13 disturbed in any way. In this connection itshould be noted that while the blank shown in FIG. 1 is plastic enoughto permit its deformation and slumping action described, there shouldstill be enough form retaining characteristic so that the remainingportion of the block will not slump merely through its own weight. Forthis reason, normally the base 21 will comprise a pallet holding, forexample, two blocks on which the blocks may be removed for final settingand curing.

In the form of the invention shown in FIG. 5, I produce a blankidentical with that shown in FIG. 1 except that a portion of the endwalls is also made higher than the remaining portion of the blank sothat slumping will not be confined to the front face of the block, butalso extend to the ends. For convenience and to shorten the description,I have applied to FIG. 5 the same reference characters used in FIG. 1with, however, the numeral 1 as a prefix to indicate modification. Whena blank such as shown in FIG. 5 is subjected to the slumping step asshown in FIGS. 2 and 3, the outside face of the rear wall 113 willremain planar and retain its original configuration, but the slumpingwill be extended to the end walls as already indicated. There areseveral reasons why slumping of the end walls may be indicated such, forexample, as instances where the end wall becomes an exterior surface asat a corner. This slumping may of course be confined to only one endwall if desired.

In FIG. 6 I show a modification in which I have also applied the samereference characters used in FIG. 1 with, however, the prefix 2 toindicate modification. In this form of the invention, however, the rearwall 213 is pre-formed preferably of a different material than theremaining portions of the block. Suitable means such as tongues 220 areprovided on the pre-formed rear wall 213 so that when the remainingportion of the block is cast around them a rigid, unitary body willresult. Preferably the rear wall 213 is formed of a suitable insulatingmaterial which may have its outside face treated to provide a permanentfinish if desired.

My invention is not concerned with the particular manner of applyingsuch a surface finish nor with the particular type of insulatingmaterial employed. Any of the conventional finishes and availableinsulating materials of adequate strength may be used. In thisconnection, it may be noted that with the remaining portion of the blockconstructed and laid to carry the load, the wall 213 may havesubstantially less compressive strength than would normally be requiredin a load-bearing wall. Among the materials which may be usedsuccessfully for the prefabricated inside wall 213 are molded cellulosicmaterials formed, for example, from wood, cork, begasse, paper pulp,ligno-cellulose and the like. Molded inorganic insulating material andmixturese may of course also be used. I may, for example, employ plasticor special cements which have been rendered porous by entraining air orgas with them. I have found, for example, that a porous, cement-typematerial sold by Borg-Warner and Company under the name Betocel issatisfactory.

The manner of forming the blank shown in FIG. 6 may be substantiallyidentical with that described for forming the blanks shown in FIG. 1,except that the pre-formed rear wall 213 is first inserted into the moldand the wet concrete mixture poured and vibrated around it. Afteremploying the final pressure step as, for example, in the mannerindicated in FIGS. 2 and 3, a final block is produced having, forexample, the general configuration shown in FIG. 7. The front wall 210is slumped as in the previously described method and the overall heightof the block is uniform with top and bottom faces planar and parallel toeach other.

In FIG. 8 I show an illustrative view of a typical finished blockproduced in accordance with the present invention. This particular blockdoes not show a separate rear wall as illustrated in FIG. 7, it beingunderstood, however, that in all other respects the configuration of theblock of FIG. 7 would be substantially identical with that shown in FIG.8. In FIG. 8 it can be seen that the front face of the block has randomirregularities produced by the slumping action, but that the top andbottom faces as well as the rear face are absolutely flat and uniform.The end faces may either be flat or slumped as desired, but in no casewill slumping of the end faces produce any deleterious disfiguration ofthe plane faces of the top, bottom and rear exterior surfaces. Thisproduces a block which can readily be laid with great accuracy and witha minimum expenditure of labor, leaving a perfectly flat interior wallsurface which can be easily and inexpensively furred out for theconventional plaster finish. It should be noted that generally speaking,irregularities at the end of the block if not pronounced, will not haveany appreciable effect in increasing the block layers time but on thecontrary will sometimes have a certain amount of advantage in producinga stronger wall.

In the drawings I have shown a specific form of block and have describedit as illustratively about 15 /2 inches long, about 7% inches wide and 3/8 inches high. This type of block is conventionally referred to as amodular 8 by 4 by 16 inch block. It will be understood that when theblock as shown in FIG. 1 or FIG. '5 is slumped there will be some changein some of the overall dimensions and this change will depend upon theamount of material which is displaced in the slumping operation.Illustratively, if a blank as shown in FIG. 1 is inches long it may beextended to approximately 15% inches overall if there is a one inchdifference between the height of the front wall and the height of therear wall. Similarly, the width may be extended from 7% inches toapproximately 7% inches. These measurements are taken at the center ofthe block in each direction and at the top face, it being understoodthat no specific measurement can be made of the random front face or endfaces where the greatest slumping action is manifest.

Those skilled in the art should also note that while for purposes ofillustration I have shown a so-called 16 inch concrete block, thepresent invention may be practiced to produce any of the usual shapesand sizes of concrete blocks employed in the industry. For example,straight facing blocks and half blocks for corners may be produced tomatch the 16 inch blocks. Also, the blocks may be made in various widthsand lengths and heights to secure special design effects or for specialtypes of construction, while still employing the features of the presentinvention.

The terms employed in the specification and claims including the wordsslump and slumped are used in the common sense in which such words areused in the industry to which the present invention relates. Such wordsas front, bottom, rear and the like are used in an identifying sensethroughout and not in a limiting or restrictive sense, except insofar asthe context may so indicate. The scope of the invention, therefore, isnot indicated by limited example in the drawings and specification, butis defined in the claims.

I claim:

1. A method of producing an improved slump block having front, rear andend walls with at least one exterior planar face which comprises firstmolding an intermediate blank having one exterior wall with the samevertical height as the desired completed block and an opposite wall ofgreater height than the first mentioned wall, ejecting said blank fromit's mold, and then compressing the said blank vertically to the sameheight as the first mentioned wall to slump the second mentioned wall torandom irregular exterior shape while leaving the first mentioned wallundisturbed.

2. A method as defined in claim 1 wherein at least a portion of endwalls connecting said first and second mentioned walls are alsoinitially formed higher than the first mentioned walls and arethemselves slumped by the said compressing step of the method.

3. A method as defined in claim 1 wherein a recess is formed between thesecond mentioned wall and end walls during the first described blankingstep, said recesses being filled by slumped material during the slumpingstep.

4. The method of producing an improved slump block which comprisespreforming a rear wall therefor having the identical height and lengthdesired in the finished block and with attaching means forming a partthereof, inserting said form'in a mold and casting wet concrete formingthe balance of the block with said attaching means imbedded in saidconcrete, at least the front wall formed by the concrete being ofgreater height than the preformed rear wall, removing the entire blockfrom the mold, and applying vertical pressure to the concrete while wetto reduce it to the height of the rear block and produce a slumped faceof randomly irregular outline on at least the outside surface of thefront block face.

References Cited in the file of this patent UNITED STATES PATENTS1,118,681 Reagan Nov. 24, 1914 1,570,595 Stevens Jan. 19, 1926 1,879,841Caswell et al. Sept. 27, 1932 2,288,559 Ward June 30, 1942 2,689,381Terriere Sept. 21, 1954 2,708,783 Ripley May 24, 1955

